Image Number 15 for United States Patent #8130628.
Shape-wise thicknesses tr1, tr2, . . . , and trN of a cover layer and first through (N-1)-th intermediate layers of an optical recording medium having refractive indexes nr1, nr2, . . . , and nrN are converted into thicknesses t1, t2, . . . , and tN which are calculated by products of a function f(n)=-1.088n.sup.3+6.1027n.sup.2-12.042n+9.1007 where n=nr1, nr2, . . . , and nrN.